Xuxi Zhang

INTRODUCTION Diabetes mellitus is a chronic disease with significant morbidity and mortality which may result in long ‐ term damage, dysfunction, and failure of organs such as retinopathy with potential loss of vision, nephropathy leading to renal failure, diabetic gangrene, and cardiovascular and cerebrovascular disease. 1 Furthermore, the prevalence rate of diabetes is increasing in countries around the world and the mortality of diabetes is also high. 2 ‐ 4 There are several types of diabetes including type 1 diabetes, type 2 diabetes, gestational diabetes and other specific diabetes types. 5 Among all the patients with diabetes, about 90%–95% have type 2 diabetes which “encompasses individuals who have insulin resistance and usually have relative (rather than absolute) insulin deficiency”. 1 The main characteristic of type 2 diabetes (T2DM) is hyperglycemia so that among patients with T2DM, the incidence of complications is strongly associated with the previous hyperglycemia. 6 According to the results of trials, epidemiological analysis and meta ‐ analysis, hyperglycemia commonly measured by glycated hemoglobin (HbA 1c ) is significantly associated with the incidence of macro ‐ vascular complications, the primary cause of death in patients with T2DM. 7 “Each 1% reduction in updated mean HbA1c was associated with reductions in risk of 21% for any end point related to diabetes, 21% for deaths related to diabetes, 14% for myocardial infarction, and 37% for microvascular complications”. 6 Therefore, glycemic control is an important part of the treatment for patients with T2DM. Patients with T2DM who want to control blood glucose effectively should make on ‐ going changes in their lifestyle including diet, exercise, medication management and monitoring clinical and metabolic parameters which require strong self ‐ management and self ‐ regulation skills. 8 Thus, patients with T2DM need not only diabetes self ‐ management education but also diabetes self ‐ management support which could help them implement and sustain key behaviors in order to control their blood glucose. 9 Peer support, a kind of ongoing support from nonprofessionals, may effectively provide ongoing self ‐ management support and help patients with diabetes change and sustain these key behaviors. 8, 10 One approach to defining peer support 10 identified four key functions of effective peer support as 1) assistance in daily management, 2) social and emotional support, 3) linkage to clinical care and community resources, and 4) ongoing availability of support. A guide developed by the Victorian Department of Human Services in Australia proposed seven types of peer support: Have a chat, Support groups, Internet and email peer support, Peer ‐ led groups or events, Individual peer coaches, Telephone ‐ based peer support, Community workers and Service provider ‐ led groups. 11 As to the effect of peer support on glycemic control, there have been many studies on the relation between peer support and glycemic control effect among patients with T2DM but the results of different trials have not been altogether consistent. Additionally, there is no guideline for the implementation of peer support. Therefore, the purpose of this review is to study the effects of peer support on glycemic control for patients with T2DM and to identify important characteristics among providers, types, intervention duration and effect duration 6 129 Peer support among adults with type 2 diabetes